Today, most electronic equipment requires access to a source of power such as electrical wall outlets or batteries that can weigh as much or more than the equipment itself. The equipment may be used where electrical outlets are unavailable. In some instances, battery packs may be recharged but again this requires an electrical wall outlet or other power source. Further, battery packs may typically only be used for a very limited time before they need to be recharged again.
As the need for alternative energy sources increases, increasingly efficient solar power systems are being developed. Known solar cell systems typically concentrate the sun's rays and often require sophisticated tracking optics to consistently capture the most intense sunlight. Solar systems capable of providing enough power to operate many devices are often bulky and heavy and thus are not practical for use in portable devices.